`detached` `child_process` using inherited `stdio` breaks the terminal control code

[davidmurdoch]

Version

21.4.0

Platform

Linux PC 5.15.133.1-microsoft-standard-WSL2 #1 SMP Thu Oct 5 21:02:42 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

child_process

What steps will reproduce the bug?

Create two files:

// index.js
const { fork } = require('child_process');

console.log("forking detached child");
const child = fork('./child.js', [], {
  detached: true
});


console.log("Waiting for child to disconnect...");
child.once("disconnect", () => {
  console.log("child disconnected");
  child.unref(); // allows the parent to shut down
});

// child.js
console.log("child is alive");

setTimeout(() => {
  console.log("child is disconnecting");
  process.disconnect();
}, 1000);


setTimeout(() => {
  console.log("child is exiting"); // this gets printed
}, 2000);

then run:

node index.js

Wait a moment until you see "child is exiting", then send a control code to your terminal, by pressing Ctrl+C, the up arrow, etc. If you press the up arrow you'll see ^[[A, and for Ctrl+C you'll get ^C^C. After pressing Ctrl+C you'll terminal will be restored.

I'm running Windows 11 with VSCode in WSL2 using GNU bash version 5.1.16(1)-release (x86_64-pc-linux-gnu). This does not occur on Windows VSCode (NOT WSL2) with Powershell (the child is exiting message doesn't appear).

How often does it reproduce? Is there a required condition?

No response

What is the expected behavior? Why is that the expected behavior?

The terminal state should not print control codes.

What do you see instead?

It prints control codes.

Additional information

No response